Turkey's prime minister has called for the Palestinian flag to finally be raised at the United Nations, insisting that international recognition of the state was now an obligation, not an option.

Recep Tayyip Erdogan used a much-anticipated speech to the Arab League in Cairo to rally opposition to Israel, and promised that Turkey would stand in solidarity with those struggling for political change in the Arab world.

"Freedom and democracy and human rights must be a united slogan for the future of our people," Erdogan told an audience of Arab foreign ministers and millions more watching on television across the region. "The legitimate demands of the people cannot be repressed with force and in blood."

The 57-year-old was speaking at the start of a four-day tour of revolutionary north Africa, which analysts believe is designed to strengthen Turkey's influence within the Middle East and isolate their one-time ally Israel. Palestinian president Mahmoud Abbas, who is also in Egypt, has announced that he will be pressing ahead with Palestine's bid for full recognition from the UN security council, despite the fact that it will almost certainly be met by a US veto. The EU's foreign policy chief, Catherine Ashton, said that the bloc has yet to reach a common position on the question of Palestinian statehood.

Erdogan is currently embroiled in a diplomatic crisis with Israel over the latter's refusal to apologise for the killing of Turkish activists by Israeli soldiers on a Gaza-bound ship last year. In his address he accused the state of acting like a spoiled child and building a blockade around its own people, adding: "Israel will break away from solitude only when it acts as a reasonable, responsible, serious and normal state."

He added: "We must work hand in hand with our Palestinian brothers. The Palestinian cause is the cause of human dignity. It's time to raise the Palestinian flag at the United Nations. Let's raise the Palestinian flag and let that flag be the symbol of peace and justice in the Middle East." The 33-minute speech was interrupted several times by bursts of applause from the assembled Arab dignitaries.

With the fight for democracy continuing to rumble through the Arab world and steadfast allies seemingly melting away, Israel appears to be facing an altered reality in the Middle East – where it could once count both the Egyptian and Turkish governments as close friends. Israeli foreign ministry spokesman Yigal Palmor refused to comment on Erdogan's address, or on earlier claims made by Erdogan that Israel's assault on the Mavi Marmara vessel constituted "grounds for war".

Erdogan's visit to Egypt has been a media circus, with thousands greeting the Turkish leader on his arrival at Cairo airport on Monday night. With his strong rhetoric on Turkish-Arab unity, high-profile satellite TV chatshow appearances and photogenic walkabouts in the capital – including an impromptu and warm meeting with street protesters campaigning for regime change in Syria and Yemen – Erdogan did little to hide his intention of positioning Turkey into a leadership role at the heart of the Arab spring.

"He's a media star, and he's making the Arab leaders look bad by going to their own home and criticising them," said Sultan Al Qassemi, an analyst of Arab affairs. "It feels a tad opportunist – particularly as it's only Israel's refusal to apologise [over the Gaza boat deaths] that has given him the space to do this – but he has the credibility because he's done so well in his own country, and he can talk from a position of strength. The question remains, will he prove to be a shining star, or just a comet that will crash and burn?"

Egyptians are looking to Turkey for political support and economic aid as the country begins to rebuild following the toppling of former president Hosni Mubarak in February. Erdogan arrived in the country accompanied by an army of 200 Turkish businessmen, and has announced plans to increase investment and establish a formal strategic co-operation council between the two nations. With Egypt's military junta on the back foot over recent pro-change protests and the breaching of the Israeli embassy during a protest in Cairo last week, this trip has come at a particularly sensitive time.

"Right now every country is trying to advance its own agenda in Egypt," said Al Qassemi. "Turkey can't match the billions of dollars being ploughed in by Saudi Arabia and the Gulf, but it can use cheap media events like this to raise Turkey's profile. The Egyptian military won't necessarily appreciate all this, but Turkey is an important ally and so they're letting him get away with it."

Erdogan also opted to make a direct intervention into some of the key internal debates currently raging over Egypt's long-term future – particularly the question of whether a forthcoming new constitution, which will be drawn up after parliamentary elections in November, should enshrine a secular or Islamic state.

"Do not be wary of secularism. I hope there will be a secular state in Egypt," Erdogan told private television channel Dream on Monday. With its combination of a secular constitution, Islamic political leadership, a strong military and relative economic prosperity, Turkey is often cited as a possible model for post-Mubarak Egypt, although the Turkish prime minister was careful not to overstate his country's role in Egyptian affairs.

Erdogan also avoided making any direct criticism of Turkey's southern neighbour Syria, where a popular uprising has been brutally repressed, leaving more than 2,500 dead.